linux-kernel - Re: [PATCH 2/2] ACPI: let BIOS fall back to legacy handling if PRM disabled

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Date:   Fri, 2 Jul 2021 22:06:09 +0800
From:   Aubrey Li <aubrey.li@...ux.intel.com>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     Aubrey Li <aubrey.li@...el.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Len Brown <lenb@...nel.org>,
        ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Dan Williams <dan.j.williams@...el.com>
Subject: Re: [PATCH 2/2] ACPI: let BIOS fall back to legacy handling if PRM
 disabled

On 7/2/21 10:02 PM, Rafael J. Wysocki wrote:
> On Fri, Jul 2, 2021 at 4:02 PM Aubrey Li <aubrey.li@...ux.intel.com> wrote:
>>
>> On 7/2/21 7:37 PM, Rafael J. Wysocki wrote:
>>> On Fri, Jul 2, 2021 at 9:03 AM Aubrey Li <aubrey.li@...el.com> wrote:
>>>>
>>>> Based on _OSC PRM bit, BIOS can choose switch from legacy handling
>>>> to using PRM. So if CONFIG_ACPI_PRMT is disabled, this bit should
>>>> not be set to let BIOS fall back to the legacy handling (such as SMI).
>>>>
>>>> Cc: Dan Williams <dan.j.williams@...el.com>
>>>> Signed-off-by: Aubrey Li <aubrey.li@...ux.intel.com>
>>>> ---
>>>>  drivers/acpi/bus.c | 2 ++
>>>>  1 file changed, 2 insertions(+)
>>>>
>>>> diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
>>>> index 60fb6a84..30a3d4a 100644
>>>> --- a/drivers/acpi/bus.c
>>>> +++ b/drivers/acpi/bus.c
>>>> @@ -303,7 +303,9 @@ static void acpi_bus_osc_negotiate_platform_control(void)
>>>>
>>>>         capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_HOTPLUG_OST_SUPPORT;
>>>>         capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_PCLPI_SUPPORT;
>>>> +#ifdef CONFIG_ACPI_PRMT
>>>>         capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_PRM_SUPPORT;
>>>> +#endif
>>>
>>> What about using if (IS_ENABLED()) instead of #ifdef?
>>
>> aha, sorry, using if (IS_ENABLED()) is better, will come up with a new version soon.
> 
> No need (see my other reply).
> 
> Thanks!
> 

Okay, thanks Rafael!